Definitions for "Unable"
Not able; not having sufficient strength, means, knowledge, skill, or the like; impotent; weak; helpless; incapable; -- now usually followed by an infinitive or an adverbial phrase; as, unable for work; unable to bear fatigue.
Used to indicate that an order couldn't be filled/executed. Eg, “Your order in the Bonds was ‘unable'.
A working order which has not yet been able to be executed.
(usually followed by `to') not having the necessary means or skill or know-how; "unable to get to town without a car"; "unable to obtain funds"
(usually followed by `to') lacking necessary physical or mental ability; "dyslexics are unable to learn to read adequately"; "the sun was unable to melt enough snow"
lacking in power or forcefulness; "an ineffectual ruler"; "like an unable phoenix in hot ashes"